If you’re suffering from excessive steering wheel vibration, wandering, or difficulty turning the steering wheel, these may be the early warning signs of a faulty steering box. Unlike a blowout, which will immediately render the car inoperable, these telltale signs are giving you advanced notice that you’ll need to either repair or replace your steering box.

But rather than repair the part, the folks at Classic Performance Products (CPP) have created the 500 Series Power Steering Box. Developed for 1955-1957 Chevrolets (CP50000) and 1958-1964 Chevrolets (CP50003), these direct-replacement units have all been factory-tested to ensure quality performance, all the while providing the ultimate driving experience.

Now one may think that the steering box does nothing more than point you in the right direction but there’s much more to it. By upgrading to a 500 Series Steering Box, owners will experience excellent road feel, increased responsiveness, and driver feedback—and long gone are the days of sloppy steering and driving down the freeway like a granny with a case of shaky hands.

Developed as a direct—and improved—replacement for the factory 605 box, it is the only steering box on the market to feature a one-piece housing with absolutely no welding. Unlike other competing brands, which are multi-piece units, they are built to perform, created to last, and introduced to give your classic car a cleaner, more supple driving experience. Of course we suggest contacting CPP customer service if you have any underhood modifications (example: three-core radiator) that may get in the way of a proper installation.

So here’s a breakdown of the two different SKUs we’re featuring in this issue:

1955-1957 Chevrolet 500 Series Steering Box (CP50000)

Manufactured with a one-piece housing with “no welding,” and all-new parts (unlike their competitors), each of these units utilize an original Pitman arm and have a 14-1 ratio. Prior to being boxed and shipped, all of CPP’s 500 Series Boxes are factory-tested to ensure they deliver the excellence you’ve come to expect.

This direct replacement for the 605 produces excellent road feel and driver feedback, eliminating leaky, sloppy steering, and they even have a conversion kit that includes the 500 Series Box with power steering hose kit and pump and early model small-block Chevy V-8 power steering pump bracket. Optional chrome finish and new Pitman arms are also available.

1958-1964 Chevrolet 500 Series Steering Box (CP50003)

The CP50003 power steering conversion gearbox for the 1958-1964 Chevrolet is the newest addition to the 500 Series Power Steering family. Installation of this unit will provide a high-performance, modern-style power steering systems and it features a 14:1 ratio unit, which provides superior directional control and road feedback in addition to a more stable feel to the driver.

CPP engineered the recirculating ball gears for low friction and increased steering response. An open-centered, rotary-type valve gives you smooth operation throughout the steering range while retaining excellent road feel. For the 1958-1964 fullsize Chevrolet Impala, the 500 Series is a direct replacement for the manual steering box and other unique features are the mounting bosses that are integrated into the casting, eliminating the need for an external bracket and lining up perfectly to your column without shims.

Works with both the original and aftermarket steering columns and sway bars. This is the very best gearbox available on the market today to convert your fullsize Chevrolet to power steering! Note: It may be necessary to use notched radiator PN AL010282ANDZ.

Specs for 500 Series Power Steering Box (PNs CP50000 and CP50003)

  • Steering Ratio: 14:1
  • Input Shat is 3/4 inch -30 spline (same as the 605 box)
  • Sector shaft is 1 inch 36-4 tapered spline (same as the original 55-64 Pitman shaft)
  • Pressure fitting is 7/16 tube (11/16-18 inv. fl.)
  • Return fitting is 3/8 tube (5/8-18 inv. fl.)

CPP has been designing and manufacturing top-quality steering, brake, and suspension components for classic GM cars and trucks, as well as other customs, for over two decades. CPP is committed to providing the most innovative, performance-driven products for the automotive aftermarket at a value that customers demand. Let’s steer our way to the following easy-step install conversion that will give you the power needed to control your classic’s steering box needs.

The CPP 1958-1964 Impala CP50003 direct-replacement power steering unit is an exact bolt-on fitment to replace your old manual steering. Begin by removing the nut under the pivot arm from your existing manual box.

Once the pivot arm nut is removed, use a pulley to separate the pivot arm from the old unit’s spline. Then remove the pivot arm nut from the steering rod.

Remove the (3) bolts to drop your old steering unit.

This CPP direct bolt-on power steering unit is an easy lineup and match bolt pattern replacement. After mounting on your new power box, place the pivot arm up to the spline and hold it in its spot with the larger nut. From there bolt on the pivot arm to the steering rod/sway bars.

Tighten the pivot arm at the large nut to slide it onto the splines.

This is the view of how the newly installed 50003 Impala Power Steering Unit looks when mounted in place.

Notice that the improvised CPP power steering unit has a unique feature that includes mounting bosses that are integrated into the casting, eliminating the need for an external bracket and lining up perfectly to your column without shims.

Take note on the clearance there is between the power steering unit and the Impala’s radiator. It may be necessary to use notch radiator PN AL010282ANDZ.

It’s time to steer this Project 1963 Impala onto the next building step.